Encapsulated circuit controlling device



July 19, 1966 K. B. PRIVAL 3,

ENCAPSULATED CIRCUIT CONTROLLING-DEVICE Filed Dec. 20, 1962 //V l/E/VTOR K. 8. PR/ VA L A 7' TOR/V5 V United States Patent 3,261,939ENCAPSULATED CIRCUIT CONTROLLING DEVICE Katharine B. Prival,Croton-on-Hudson, N.Y., assignor to Bell Telephone Laboratories,Incorporated, New York, N.Y., a corporation of New York Filed Dec. 20,1962, Ser. No. 246,193 6 Claims. (Cl. 200-87) This invention relates tocircuit controlling devices and, more specifically, to reed devices ofthe switch, relay, or transfer type.

In general, circuit controlling devices of the reed type comprise aplurality of conducting elements encapsulated within a sealed container;the number depending upon the design function of the device. All, orsome of the elements, are usually made from materials sensitive tomagnetic forces and the most usual encapsulating material is glass.

The transfer type switch presented by a substantial part of the priorart comprises three electrically conducting elements sealed in adefinite geometric pattern in the extremities of an elongated glasstube. For the purpose of description, the elements can the referred toas a front contact member, back contact member, and a swinger contactmember. The geometric pattern previously referred to generally comprisesthe sealing of the back contact contiguous to the swinger in contrast tothe spaced positioning of the front contact. The individual contacts canbe fixed in either end of the tube depending on the mechanicalconfiguration desired.

The device, as described above, is in the unoperated position, that iswith the swinger in electrical continuity with the back contact. Theoperated position is acquired by subjecting the device to an appropriateactuating force such as a magnetic force or force field. This can beaccomplished by bringing the encapsulated structure into physicalproximity of a permanent magnet, magnetic field, or by passing currentthrough turns of wire that have been wound around the glass tube. If theswinger and front contact are of magnetic material or if all the contactmembers are of magnetic material but a preferential flux path has beenestablished between the swinger and the front contact due to theirphysical design, proximity, and material, the swinger will traverse thespacing between it and the front contact. By establishing electricalcontinuity between the swinger and the front contact and a space or opencircuit between it and the back con-tact, the switching or transferfunction of the device will be performed. The last described situationis called the operate, operated, or transfer position.

When the actuating or magnetic force is terminated by removing themagnet or ceasing the flow of current through the turns of wire, theswinger returns to its natural, free, or unoperated position contiguousto the back contact. In order to insure the return of the swinger memberto contiguity with the back contact, it is desirable to prestress, insome way, the two latter mentioned elements against each other. Theprestressing creates an adequate contact force between the swinger andback contact to secure electrical continuity but because of thedimensions of the various elements, their critical spacing, and physicalproperties, serious problems are encountered in the manufacture ofdevices similar to the invention.

In particular, the physical dimensions of the electrical elements formedfrom magnetic material determine the limits of magnetic flux that can begenerated within the elements before they become saturated. The physicaldimensions further define the force necessary to deflect the swingeracross the gap between it and the front con- "ice tact. Therefore, thecross sections of the elements must be large enough to allow the buildup of magnetic forces suflicient to attract the movable members acrossthe air gap yet not so great that the force required to move the swingeracross the space cannot be generated before i the elements becomemagnetically saturated. The spacing between the elements is alsocritical because it directly affects the force necessary to close thegap between the swinger and the front contact.

In addition, if the prestressing between the swinger and the backcon-tact is too great, there is a tendency for the back contact tofollow the swinger, when it is magnetically operated, across the spacingand short circuit all three elements. If it is too little, when themagnetic biasing is released, the swinger and back contacts might have atendency to oscillate which may result in intermittent breaks inelectrical continuity called chattering. This directly affects the speedor response of the device since it is extremely difficult to accuratelyoperate the mechanism when any of its parts are in motion.

Obtaining the proper magnitude of prestressing between the movable orswinging member and the back contact introduces further problems. If thedegree of prestr-essing between the movable member and the :back contactand the critical spacing of the elements within the envelope tareattempted to be defined before they are sealed in the encapsulatingmaterial, the heating and cooling of the material may substantiallyalter or anneal away the desired properties and can, in some instances,introduce unwanted patterns.

The critical problem therefore arises in establishing, during themanufacturing process, the contact force between the swinger element andthe back contact and the spacing of the various elements within thedevice once the physical dimensions of the elements have beendetermined.

It is an object of the invention to improve the construction andoperation of these devices.

Another object is to improve the manufacturing proc esses and techniquesinvolved in producing reed type devices.

A further object is to provide control and adjustment of the contactforce between the various electrical elements contained within reed-typedevices.

A specific object is to improve the structure of miniature encapsulateddevices by providing a working access or aperture to the interior of thecontainer.

Another specific object of the invention is to improve the operation ofminiature switching devices by diminishing the deflection of a movablemember required to produce an adequate degree of contact force.

In accordance with the preferred embodiment of the invention, itcomprises a plurality of elements sealed within the ends of an elongatedtubular container or envelope. At least one of the sealed elements is atube or duct mem her through which an electrical conductor can beinserted until it comes into physical and electrical contact, on theinside of the envelope, with another of the elements that has been fixedin an envelope end. The inserted member becomes the back contact and theother element becomes the movable or swinger member. The contact forcebetween the members can be adjusted and controlled by the depth ofinsertion of the back contact member. When the proper degree of contactforce has been obtained, a portion of the duct or tube can be physicallydeformed or crimped and sealed about the wire inserted therethrough.

Such a structure provides obvious advantages. All.

elements of the device can be sealed within the ends of the glasscontainer in a free or unstressed condition while the containermaterial, glass in most instances, is hot without fear of annealing awayany desired stress patterns.

The stresses or contact forces desired between the swinger and backcontact members are induced through the insertion process when thecontainer material is cold thereby alleviating the problem of annealingthe sealed members.

Another advantage is the furnishing of a means of controlling andadjusting the amount of contact force by the insertion of the backcontact through the tube.

A still further advantage of the device is that it can be purged ofatmospheric imperfections by filling and sealing an inert gas within theglass envelope or container. The container can be filled afterstructural completion through the tube that contains the back contactmember before it is crimped and sealed closed.

The advantages of the invention are obtained through its features one ofwhich is the sealing within one end of an elongated glass container,along with a plurality of electrically conducting elements, of a tubethrough which a back contact member may be inserted and which providesaccess for the purposes of controlling and adjusting contact forces,spacing of elements, and through which atmospheric conditions can bedefined.

Another feature is a special movable member having a leaf or auxiliarycantilever spring attached in such a way as to enhance the contact forcebetween the member and another conductor for a given deflection of themember.

Other objects, advantages, and features will be obvious and understoodfrom the following detailed description, when read in conjunction withthe drawing, in which:

FIG. 1 is a sectional view of one embodiment of the invention;

FIG. 2 is a sectional view taken generally along line 22 of FIG. 1;

FIG. 3 is a sectional view of another embodiment of the invention;

FIG. 4 is a sectional view of a still further embodiment of theinvention having a special swinger member; and

FIG. 5 is a plan view of the special swinger member that is incorporatedin the device of FIG. 4.

In accordance with the various figures and specifically with referenceto FIGS. 1 and 2, the device comprises an elongated container sealed inthe ends of which are a variety of elements including an aperturedelement or an access tube 11 and two reed members 12 and 13. Thoseportions, including the ends, of the members 12 and 13 that areencapsulated within the container 10 are flattened in cross section intoa ribbon or reed-type generally rectangular cross section. One dimensionof the rectangle is much greater than the other dimension and the reeds,therefore, have a tendency to bend preferentially in the direction ofthe smaller rectangle dimension. For the purpose of disclosure, themovable member 12 will be designated as a swinger or swinger member andthe member 13 will be designated as a front contact or front contactmember,

The swinger 12 and the front contact 13 are held within the container 10such that their ends 15 and 16 respectively, are in a spaced apartrelationship in the unoperated position shown in FIGS. 1 and 2. Theapertured element or access tube 11 is held in the end of the container10 such that its axial line intercepts the swinger 12 near its end 15. Aback contact 14 crimped within the access tube 11 is in electrical andphysical contact with the swinger end 15.

The invention is assembled by sealing the tube 11 and the two reedmembers 12 and 13 in the ends of the container 10 while the containermaterial is still hot. Because the elements are in a free position andnot in a defiected or prestressed state, the heat from the containerdoes not affect them in that it cannot anneal away any desired contactforces or stresses that are to be subsequently generated. After thecontainer material has cooled, the back contact 14 is inserted throughthe access tube 11 until it contacts the swinger end 15. It is apparentthat the degree of insertion of the back contact 14 within the tube 11determines the contact force between the back contact 14 and the swingerend 15 and the gap spacing between the swinger end 15 and the frontcontact end 16. The contact force and reed spacing, can be controlledand adjusted by the amount of insertion of the back contact 14. Thecontact force and spacing of the elements 12 and 13 are not subject tothe annealing heat of the hot container material because they areestablished subsequent to the cooling of the container 10.

After the desired amount of contact force between the swinger 15 and theback contact 14 has been established, a portion of the duct or accesstube 11 may be crimped, or in some other similar manner, physicallydeformed and sealed around the back contact 14 to fix or makingpermanent the physical relationship of the elements within the container1%. It is to be noted that the access tube 11 can further be used todefining the atmosphere inside the container 10 if a specialenvironment, such as an inert argon atmosphere, is desired.

The invention is operated by subjecting it to an actuating force such asa magnetic force field. Such a field may be generated by passing acurrent through turns of wire 27 that have been wound around thecontainer 10. The swinger 12 and the front contact 13 are formed frommaterial sensitive to magnetic forces. The current passing through thewire turns induces lines of magnetic flux in the two members. As aresult of the magnetic force field in the air gap, the swinger end 15 isattracted away from the back contact 14 and to the front contact end 16.Electrical continuity then exists between the swinger 12 and the frontcontact 13. When the current is stopped or the magnetic field removed,the swinger 12 snaps back against the back contact 14.

The above discussion of the magnetic operation is of a summary nature inthat it is well known in the art and not part of the novelty of thisinvention. In conjunction with the prior art, it is also well known thatthe back contact can be either of magnetic or non-magnetic materialwithout affecting the operation of the device.

FIG. 3 illustrates another embodiment of the invention in that thedevice shown is capable of a multiplicity of switching functions. FIG. 3describes a device comprising an elongated container having sealed ineach of its ends a reed member and an access tube. In end 19 ofcontainer 20 is sealed a swinger member 12 and an access tube 11 whilein end 21, access tube 18 and front contact member 13 are sealed.Crimped or permanently fixed within the tube 11 is a back contact member14 and within tube 18 is a second back contact member 17. The device isassembled as previously described with relation to the switchillustrated in FIGS. 1 and 2.

The invention as shown in FIG. 3 is in an unoperated position, that is,the swinger end 15 is contiguous to the back contact member 14 and thefront contact end 16 contiguous to the second back contact 17. When thedevice is subjected to a magnetic force field or operated, the fieldattracts the swinger end 15 and the front contact end 16 to each othertransferring electrical continuity from members 12 and 14, and 16 and 17to members 12 and 16. Air gaps or electrical discontinuities areestablished between the elements 14 and 15 and between the elements 16and 17. The removal of the magnetic force allows the device to snap backto its previously described unoperated position. The operation of thedevice described above is only exemplary of a number of switchingcombination possibilities inherent in such a device and obvious to thoseskilled in the art.

FIG. 4 illustrates a further embodiment of the invention wherein thedevice shown in FIG. 1 is modified with the special swinger member 22shown in FIG. 5. A leaf or auxiliary cantilever spring member 24 isfastened to the main portion or flattened section 23 of the reed on theside adjacent the back contact 14. The leaf 24 is attached to the reed23 at a point 25 distant from the reed end 26 and so located that whenthe back contact 14 is inasensao sorted into the tube 11, the backcontact 14 comes into contiguity with with the member 24.

The spring constant of the leaf 24 is large enough to prevent thedeflection of it into physical contact with the main portion 23 when thedesired contact force is obtained. The incorporation of the auxiliarycantilever spring member 24 shortens the effective lever arm of the reedbecause when the leaf 24 is deflected by the back contact 14, theresulting force applied towards the deflection of the reed Z3 isessentially, in effect, applied at the attaching point 25 and not theend 26 where the force Would normally be applied. The reed lever arm hasbeen shortened by approximately a distance equal to the difference ofthe reed length between its end 26 and the lever attaching point 25. Theresult and importance of shortening the effective reed lever arm is tosupply at least an equal amount of contact force for a smallerdeflection of the reed end 26 than would normally be obtained by thesame deflection of the reed end in the device shown in FIG. 1.

The manufacture and operation of the device shown in FIG. 4 is similarto those previously described.

Although three embodiments of the invention have been disclosed, it willbe obvious to those skilled in the art that modifications too numerousto mention, some of which have been alluded to in the specification, maybe made Without departing from the scope of this disclosure and theappended claims.

What is claimed is:

1. A controlling device comprising a hollow container having a firstcontact, a movable element, and a duct member sealed within the walls ofsaid container, said member including a deformable portion, a secondcontact extending through said member, said element being spaced fromand overlapping said first contact, said element further comprising areed-type main portion having a free end and an auxiliary cantileverleaf juxtaposedly secured to said main portion at a point distant fromsaid free end, said leaf being spaced from said main portion at alltimes, said second contact being in physical and electrical continuitywith the free end of said leaf, said leaf providing at least the samecontact force between said leaf and said second contact for a smallerdeflection of said main portion than would be obtained by the samedeflection of said main portion by said second contact being incontinuity to said main portion, because of the effective foreshorteningof the lever arm of said element, said deformable portion beingphysically deformed about said second contact sealing the inside cavityfrom the outside environment of said container and, actuating meansoperatively influencing said element between said first and secondcontacts.

2. A controlling device comprising an elongated tubular container sealedon both ends having a first contact, a swinger member and a tube sealedin its ends, said tube having a deformable portion and a second contactcontained therein, said swinger comprising a reed-type main portionhaving a free end and an auxiliary cantilever leaf juxtaposedly securedto said portion at a point distant from said free end, said leaf beingspaced from said portion at all times, said second contact being inelectrical continuity with the free end of said leaf, said swingermember located between said second contact and said first contact andspaced from said last named contact, and actuating means operably movingsaid swinger between said first and second contacts.

3. A switch device comprising a hollow container having at least onemovable element and at least one'tube sealed within the walls thereof,said tube further having a deformable portion and an electricalconductor sealed within, said element comprising a main portion having afree end and an auxiliary cantilever leaf juxtaposedly secured to saidportion at a point distant from said end, said leaf being spaced fromsaid portion at all times, said conductor being in physical andelectrical continuity with said leaf of said element, and actuatingmeans external to said container operatively moving said element awayfrom said conductor and disrupting said continuity.

4. A controlling device comprising a hollow container having a pluralityof movable elements and a plurality of tubes sealed within the wallsthereof, said tubes having deformable portions and electricallyconducting means sealed within, each of said elements further comprisinga main portion having a free end and an auxiliary cantilever leafjuxtaposedly secured to said portion at a point distant from said end,said leaf being spaced from said portion at all times, said means beingcontiguous to said leaves of said elements and said elements being in aspaced and overlapping relationship to each other, and actuating meansoutside of said container operatively influencing said elements awayfrom said means and contiguous to each other.

5. A controlling device comprising a hollow container having at leastone electrically conducting element and a plurality of apertured memberssealed within the walls thereof, each of said members further havingdeformable portions and electrically conducting means sealed therein,said element further comprising a main portion having a free end and anauxiliary cantilever leaf juxtaposedly secured to said portion at apoint distant from said end, said leaf being spaced from said portion atall times, one of said conducting means contacting said leaf of saidelement and the other means being overlapped and spaced therefrom, andactuating means outside of said container operatively moving saidelement between said spaced means.

6. A controlling device comprising a hollow container having a pluralityof electrically conducting means and at least one apertured elementsealed Within the Walls thereof, said element comprising a tube having adeformable portion, one of said means being a movable member, said meansbeing in a spaced and overlapping relationship with each other withinthe interior of said container, said member further comprising a mainportion having a free end and an auxiliary cantilever leaf juxtaposedlysecured to said main portion at a point distant from said end, said leafbeing spaced from said main portion at all times, said conductor beingsealed within said tube by said deformable portion of said element aboutsaid conductor, said conductor being contiguous to said leaf, andactuating means outside of said container operatively moving said memberaway from said conductor and into contiguity with another of said firstnamed means.

References Cited by the Examiner UNITED STATES PATENTS 2,922,856 1/ 1960Karrer 200-87 2,925,646 2/1960 Walsh 29-155.5 3,032,628 5/1962 Elwood200-87 3,098,908 7/1963 Heath 200-87 3,100,813 8/1963 Rice et al.17450.56 3,147,538 9/1964 Perkins 29-1555 FOREIGN PATENTS 126,873 2/1948 Australia. 450,525 4/ 1945 Great Britain.

BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner.

B. DOBECK, Assistant Examiner.

2. A CONTROLLING DEVICE COMPRISING AN ELONGATED TUBULAR CONTAINERSELECTED ON BOTH ENDS HAVING A FIRST CONTACT, A SWINGER MEMBER AND ATUBED SEALED IN ITS ENDS, SAID TUBE HAVING A DEFORMABLE PORTION AND ASECOND CONTACT CONTAINED THEREIN, SAID SWINGER COMPRISING A REED-TYPEMAIN PORTION HAVING A FREE END AND AN AUXILIARY CANTILEVER LEAFJXTAPOSEDLY SECURED TO SAID PORTION BEING SPACED POINT DISTANT FROM SAIDFREE, END SAID LEAF BEING SPACED FROM SAID PORTIOIN AT ALL TIMES, SAIDSECOND CONTACT IN ELECTRICAL CONTINUITY WITH THE FREE END OF SAID LEAF,SAID SWINGER MEMBER LOCATED BETWEEN SAID SECOND CONTACT AND SAID FIRSTCONTACT AND SPACED FROM SAID LAST NAMED CONTACT, AND ACTUATING MEANSOPERABLE MOVING SAID SWINGER BETWEEN SAID FIRST AND SECOND CONTACTS.